Have you noticed any distant map detail similarities between Doom engine -games and other FPSs?
For example, when I played Heretic E2 for a long time and reached E2M7's secret with the wooden stages, it reminded me of the Doom TNT Map12 crates at the blue key door. These parts don't even look like each other but the layout gave me this impression.
At one point, I forgot the structures of the Wolf3D levels. There's a part in E2L2 which reminds me of Heretic E2M2's Y-shaped room beyond the yellow doors.
Duke3D E1L4's bunker made me recall Heretic E1M6's ''secret'' which was part of the level progression. Probably because of the monsters and items behind that window, idk.